Fructosamine and glycated hemoglobin in the assessment of glycaemic control in dogs Araceli Loste, M. Carmen Marca To cite this version: Araceli Loste, M. Carmen Marca. Fructosamine and glycated hemoglobin in the assessment of gly- caemic control in dogs. Veterinary Research, BioMed Central, 2001, 32 (1), pp.55-62. 10.1051/ve- tres:2001109. hal-00902686 HAL Id: hal-00902686 https://hal.archives-ouvertes.fr/hal-00902686 Submitted on 1 Jan 2001 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Vet. Res. 32 (2001) 55–62 55 © INRA, EDP Sciences, 2001 Original article Fructosamine and glycated hemoglobin in the assessment of glycaemic control in dogs Araceli LOSTE*, M. Carmen MARCA Department of Animal Pathology, Veterinary Faculty, University of Zaragoza, Miguel Servet 177, 50013 Zaragoza, Spain (Received 12 May 2000; accepted 17 October 2000) Abstract – Fructosamine and glycated hemoglobin (HbA1c) concentrations were measured simul- taneously in 222 dogs (96 healthy and 126 sick dogs). The dogs were divided into 3 groups accord- ing to the glucose concentration: hypo, hyper and euglycaemic dogs. Serum fructosamine concen- trations were measured by the reduction test with nitroblue tetrazolium. A turbidimetric inhibition immunoassay and specific polyclonal antibodies were used to evaluate glycated hemoglobin con- centrations. A significant correlation was found between glucose concentration and either fruc- tosamine (r = 0.63, p < 0.0001) or glycated hemoglobin (r = 0.82, p < 0.0001). The correlation was higher in hyperglycaemic dogs for fructosamine (r = 0.80, p < 0.0001) and in hypoglycaemic dogs for glycated hemoglobin (r = 0.91, p < 0.005). We found a significant correlation between serum fruc- tosamine and glycated hemoglobin (r = 0.65, p < 0.0001) when all the dogs were studied. A signif- icant correlation was observed between serum fructosamine and glycated hemoglobin only in hyper- glycaemic dogs (r = 0.82, p < 0.0003). Thus, fructosamine and HbA1c may be considered for use in screening tests for diabetes mellitus in dogs and clinical tests for monitoring control and evaluation of the diabetic animal’s response to treatment. The choice of the analytical assay depends on the characteristic and analytical opportunities of the laboratory, as well as the number of serum samples to be analysed. fructosamine / glycated hemoglobin / glycaemic control / dog Résumé – Utilisation de la fructosamine et de l’hémoglobine glycosylée dans l’évaluation de la glycémie des chiens. Les concentrations de fructosamine et d’hémoglobine glycosylée (HbA1c) ont été évaluées chez 222 chiens (96 sains et 126 malades). Les chiens ont été répartis en 3 groupes : chiens hypo, hyper et normoglycémiques. La concentration de fructosamine a été déterminée par réduc- tion du bleu de nitrotétrazolium. Le dosage de l’hémoglobine glycosylée a été fait selon une technique immunologique. Les auteurs ont trouvé une corrélation significative entre la concentration en glucose et la fructosamine (r = 0,63; p < 0,0001) d’une part, et entre la concentration en glucose et l’hémo- globine glycosylée (r = 0,82; p < 0,0001) d’autre part. La corrélation était plus forte chez les chiens hyperglycémiques (fructosamine r = 0,80; p < 0,0001) et hypoglycémiques (hémoglobine glycosylée * Correspondence and reprints Tel.: (34) 976 76 15 76; fax: (34) 976 76 16 12; e-mail: [email protected] 56 A. Loste, M.C. Marca r = 0,91; p < 0,005). La fructosamine était significativement corrélée à l’hémoglobine glycosylée (r = 0,65; p < 0,0001) chez l’ensemble chiens. Une corrélation significative entre l’hémoglobine glycosylée et la fructosamine a été observée uniquement chez les chiens hyperglycémiques (r = 0,82; p < 0,0003). La mesure des concentrations en fructosamine et en HbA1c peut être considérée comme test de dépistage de diabète sucré chez le chien et comme test clinique utile pour le contrôle et l’éva- luation de la réponse de l’animal diabétique au traitement. Le choix de l’un ou l’autre test analy- tique dépend des possibilités du laboratoire, ainsi que du nombre d’échantillons sanguins à analyser. fructosamine / hémoglobine glycosylée / contrôle de la glycémie / chien 1. INTRODUCTION between both parameters and their diag- nostic usefulness [1, 14, 15]. Thus, the pur- The evaluation of carbohydrate pose of the present study was to analyse the metabolism has been enhanced through the correlations between fructosamine/glucose development of methods for monitoring and HbA1c/glucose concentrations in hypo, long-term glycaemic conditions, such as hyper and euglycaemic dogs, and to evalu- fructosamine and glycated hemoglobin ate the correlation between fructosamine (HbA1c) measurements. Fructosamine and and HbA1c measurements in canine blood HbA1c are both blood proteins that are samples. widely used to monitor glycaemia in human patients, especially in the diagnosis and monitoring of diabetes mellitus. 2. MATERIALS AND METHODS Serum fructosamine is formed through non-enzymatic irreversible reactions 2.1. Animals between glucose and serum proteins. Fruc- tosamine concentration directly depends on The study population consisted of the blood protein concentrations and their 222 dogs of different ages, sex and breeds composition [12, 17, 18] and on the plasma from the Small Animal Internal Medicine glucose concentration. In dogs, because the Department at the Veterinary Faculty of average life of albumin is 8.2 days, the fruc- Zaragoza (Spain). The dogs were divided tosamine concentration reflects glycaemic into the following 3 groups. status over the previous 1 to 3 weeks [8, 10]. The first group included dogs with insuli- Glycated hemoglobin is the product of a noma (n = 5). The diagnosis of insulinoma slow, nonenzymatic and irreversible pro- was confirmed on the basis of history, phys- cess and it is directly related to serum glu- ical examination findings, serum glucose cose concentration and erythrocyte lifespan and insulin concentrations, and the good (120-day-lifespan). Hemoglobin A1c is the response to treatment. Post mortem studies most important glycated fraction of the corroborated the diagnosis of insulinoma in hemoglobin molecule [19, 20]. With a nor- all of these dogs. mal turnover of erythrocytes, HbA1c pro- The second group (n = 205) included vides an accurate index of the average glu- either healthy dogs (history, physical exam- cose concentration over the preceding 2 to ination and results of routine clinicopatho- 3 months [3, 5]. logic examinations: cell blood count, serum Although it is known that prolonged hypo biochemical analysis and complete urine and hyperglycaemia modify serum fruc- analysis were normal) or dogs with different tosamine and HbA1c concentrations, there diseases (gastrointestinal, respiratory, para- is little information on the correlation sitic, etc.). Glycated proteins in dogs 57 The third group included dogs with dia- 2.2. Sample collection betes mellitus (n = 12). In these dogs, dia- betes was newly identified or was consid- The dogs were fasted for 12 hours before ered as having a poor response to treatment. the collection of each blood sample. Blood Sequential glucose evaluations were per- samples were collected from the jugular formed on all the animals during one month. vein and were placed in EDTA-tubes and Only those with persistent low, normal or tubes without anticoagulant. Serum was high glycaemic level were included in the obtained by centrifugation (2400 g, 10 min). following final experimental groups: Blood and serum samples were divided into – group 1 (n = 7) (hypoglycaemic dogs): several portions and stored at –20 °C until glucose < 3.3 mM; their analysis. – group 2 (n = 190) (euglycaemic dogs): glucose = 3.3–6.6 mM; 2.3. Analytical procedures – group 3 (n = 25) (hyperglycaemic dogs): ≥ glucose 6.6 mM. Fructosamine was measured by a reduc- The number of animals per group in the tion test with nitroblue tetrazolium (Fruc- Tables I and II is not coincident because tosamine MRP3, Ref. 1054686, Boehringer both fructosamine and glycated hemoglobin Mannheim, Barcelona, Spain) on an auto- concentrations could not be analysed in all matic analyser (Technicon RA-500, Bayer, the animals. Barcelona, Spain), using controls supplied Table I. Fructosamine concentrations (mean ± SD) in dogs with different levels of glycaemia. Groups Number of animals Fructosamine (µmol·L–1) Hypoglycaemic dogs Glucose < 3.3 mmol·L–1 7 215.2 ±41.0*** Euglycaemic dogs Glucose = 3.3-6.6 mmol·L–1 125 276.0 ±52.2*** Hyperglycaemic dogs Glucose ≥ 6.6 mmol·L–1 24 350.1 ±110.48*** *** p < 0.0006. Table II. Levels of glycated hemoglobin (expressed as HbA1c/Tot. Hb) (mean ± SD) in dogs with different levels of glycaemia. Groups Number of animals HbA1c (% of total Hb) Hypoglycaemic dogs Glucose < 3.3 mmol·L–1 7 1.0 ±0.4*** Euglycaemic dogs Glucose = 3.3–6.6 mmol·L–1 100 1.4 ±0.3*** Hyperglycaemic dogs Glucose ≥ 6.6 mmol·L–1 16 3.4 ±2.4*** *** p < 0.0004. 58 A. Loste, M.C. Marca by the manufacturer. This analytical test 3 groups of dogs were calculated by a was validated in dogs [7, 11]. Kruskal-Wallis non-parametric analysis. Glycated hemoglobin was evaluated by Linear regression and correlation analysis a commercial immunological in vitro assay (StatView) were used to determine the lin- (Tinaquant®Hemoglobin A1c II, Ref. ear relationship between fructosamine/glu- 1488414, Boehringer Mannheim, Barcelona, cose, glycated hemoglobin/glucose and fruc- Spain) applied to the same autoanalyser. The tosamine/glycated hemoglobin. instrument calculates the HbA1c/total Hb concentration ratio and expresses HbA1c results as a fraction of total Hb.